The semiconductor integrated circuit industry has experienced rapid growth in the past several decades. Technological advances in semiconductor materials and design have produced increasingly smaller and more complex circuits. These material and design advances have been made possible as the technologies related to processing and manufacturing have also undergone technical advances. In the course of semiconductor evolution, the number of interconnected devices per unit of area has increased as the size of the smallest component that can be reliably created has decreased.
Another trend in the industry is an increase in the diameter of substrates on which semiconductor devices are formed. Over the years, transitions have been made in the industry from 100 to 200 millimeters, from 200 to 300 millimeters, and now from 300 to 450 millimeters. As the substrates have increased in size, the difficulty of forming uniform material layers on a wafer has increased as well. Current deposition chambers have not been completely satisfactory is creating such material layers.
Aspects of the present disclosure may be best understood by viewing the accompanying figures with reference to the detailed description provided below.